This chapter has given you a broad view of the QoS theories and mechanisms at Layer 2
and Layer 3, but hopefully left you hungry for more details. Those details are coming in
each of the remaining chapters of this book. Now that you are familiar with the RFCs and
overall concepts that drive the development of QoS mechanisms on Cisco devices, you will
read about the very speciﬁc and often intricate details of these mechanisms on Cisco
Catalyst platforms. You may ﬁnd, as you read through some of the more detailed chapters,
that you want to refer back to this chapter to see where a speciﬁc implementation detail ﬁts
into the end-to-end QoS strategy.
The next chapter includes a broad overview of QoS feature support on all Catalyst switches,
and then focuses on QoS speciﬁcs on the Catalyst 2900XL, 3500XL, and 4000 CatOS
Family of switches.
As you read the implementation speciﬁcs in the following chapters, keep an eye on the big
picture of end-to-end QoS. From the Catalyst 3550 Family of switches to the Catalyst 4000
IOS Family of switches to the Catalyst 6500 Family of switches, think about how the
conﬁguration of each platform can be customized to ﬁt the exact needs of your network.
After all, you want to build a custom QoS policy that allows for the use of all the platforms
in a single network, with a single end-to-end policy.